A fishplate is a flat piece of metal joining one rail or beam to another. The beam joints can be strengthened by iron fishplates. A fishplate is a metal or wooden plate that is bolted to the sides of the ends of two rails or beams, to join them. In rail terminology, a fishplate, splice bar or joint bar is a metal bar that is bolted to the ends of two rails to join them together in a track. The name is derived from fish, a wooden bar with a curved profile used to strengthen a ship's mast.